Method and device for analysing chemical or biological samples

ABSTRACT

The present invention relates to a method, and to a corresponding device, for analyzing chemical or biological samples in which chemical or biological samples and/or targets (probes) are applied in the form of individual defined spots to an outer cylindrical jacket surface of a support, or are aliquoted in the form of fluid droplets into drill holes which are chased in the jacket surface of the support. The support is inserted into a recess in a retainer, which recess is essentially complementary to the cylindrical jacket surface, the samples and/or targets are acted upon by way of physical and/or chemical interactions, and the correspondingly modified spots are then analyzed. The invention accordingly relates to the use of a novel support system for investigating chemical or biological samples, which system, in contrast to conventional planar biochips, is characterized by a cylindrical geometry, with it being possible to apply, for example immobilize, substances on the functionalized jacket surface of the cylinder or in radial drill holes which are chased in the cylinder jacket. Combining this with a complementary retainer results in an analytical system which provides unambiguously defined reaction volumes, which is easy to standardize and which can be automated to a high degree.

[0001] The invention relates to a method and to a device for analyzingchemical or biological samples. In particular, the present inventionrelates to a novel support system for chemical or biological assays, inparticular for use in DNA or RNA analysis, with it being possible forthe biological probes or samples to be immobilized to be, for example,DNA, RNA, cDNA, oligonucleotides or PNA oligos.

[0002] Discovering new genetic information, or recognizing known geneticinformation, is an elementary molecular biological task, to achievewhich a large number of different methods have already been proposed.High-throughput detection techniques are increasingly coming into use inorder to make it possible to handle the enormous amount of geneticinformation in biological systems. A popular representative of thesetechniques is the DNA CHIP, or the DNA array, which, by using a highdensity of applied probes (>1 000 per cm²), enables many thousandsamples to be analyzed simultaneously. In this connection, use isprincipally made of a conventional glass microscope slide whose planarsurface is coated with DNA-binding reagents. In connection with genomicapplications, the probes which have been loaded on and bound are termedtarget sequences or targets. The targets have frequently already beenidentified genetically, which means that the gene sequence, and also inmany cases the physiological function of the targets in the relevantorganism, are known. This prior target information can be used tointerrogate new systems, to establish relationships or differences, toperform classifications or to investigate the biological purpose andfunction of the system. The biol. system to be investigated is applied,as the sample, to the slide and then hybridized. This involves thetarget DNA, which is fixed to the carrier surface, and the sample DNA,which is complementary to the target, locating each other and enteringinto a bond. If the sample DNA is, for example, labeled with a dye, thetarget can then subsequently be detected and the site or the position onthe DNA array can be used to classify, and thus obtain preparatoryinformation on, the target. Hybridization to a DNA array can be used forqualitatively and/or quantitatively analyzing complex geneticinformation.

[0003] Northern and Southern blots, and also in-situ hybridization, areclassical applications of this nature. For this, the samples are as arule prepared appropriately and investigated using defined DNA targets.Substances, i.e. what are termed labels, which can be identified usingsuitable detection methods are employed for labeling the samples.Radioactive labels, and also chemiluminescent or fluorescent labels, areparticularly widely employed. In this connection, fluorescence methods,in particular, have a high standing in chemical and biological analysisand diagnosis. These methods are very powerful detection methods whichcan be performed without using any radioactivity and, if necessary,without using any toxic substances. There nowadays exist sensitivedetection systems which even make it possible to detect individualfluorescent molecules. In addition, a large number of very differentfluorescent dyes are available, such that it is possible to haverecourse to suitable fluorescent labels for most wavelength ranges inthe visible spectrum and also in the adjoining ultraviolet or infraredspectral range. It is frequently even possible to use severalfluorescent dyes, having different excitation and/or emissionwavelengths, in parallel when carrying out a measurement.

[0004] In the present instance, a solid support is understood as being amaterial which has a rigid or semirigid surface. Supports of this naturecan, for example, be particles, strands, in particular fiber bundles,spherical bodies, such as spheres or spherules, precipitation products,gels, sheets, tubes, receptacles, capillaries, disks, films or plates.Flat supports are normally used.

[0005] As a result of progressive miniaturization, it has by now becomepossible to reduce the DNA spaces substantially such that it is nowadayspossible to arrange a large number of spaces, which can be distinguishedboth from a point of view of process technology and measurementtechnology, on a single support. In imitation of semiconductortechnology, reference is therefore made to chips, in particularbiochips, gene chips, etc. The targets are bound to the support at ashigh a density as possible. In particular, the application ofphotolithographic manufacturing techniques derived from semiconductortechnology has led to decisive advances in the production of thesechips. The principle is based on light-directed chemical solid phasesynthesis in which photolithographic masks image the spaces (cf., forexample, Fodor et al., “Light-directed, spatially addressable parallelchemical synthesis”, Science, vol. 251, 767-773 (1991)). This method isparticularly advantageous when the target DNA is to be synthesized fromindividual nucleotides in situ on the support. Thus, a particularbuilding block can be selectively added on to the targets which are inthe process of being synthesized on particular spaces while the probeson the remaining spaces remain unaffected. In this way, it is possibleto produce, on a large scale, DNA oligochips which, when usedcombinatorially, enable new sequences to be discovered. In order torecognize sought-after sequences, the oligosynthesis chip requireselaborate pattern recognition. Methods for this purpose are described indetail in international patent applications WO 90/15070, WO 91/07087, WO92/10092, WO 92/10587, WO 92/10588 and in U.S. Pat. No. 5,143,854.

[0006] In contrast to the synthesis arrays, spotting arrays, in whichthe previously produced DNA sequence is transferred in complete form tothe support, are increasingly being used in practice. Different methods,such as inkjet spotting, solid pin spotting or microprinting, are usedfor applying the DNA solution. Arrays of this nature are suitable for alarge number of applications, starting with the sequencing of DNA andproteins and proceeding all the way to DNA finger-printing and diseasediagnosis. Commercial biochips, containing a large number of differentcDNAs for hybridization, are by now being offered for sale. These cDNAsare nucleic acid sequences having lengths of from about 200 to 600 basepairs (bp. It is precisely in the area of gene expression profiling,that is identifying the state of activity of genes of interest, that thespotting chip comes into its own. In this connection, a control DNA poolis always compared with a stimulated DNA pool and changes in geneactivity thus determined for the given problem or the relevantbiological model. Chip technologies are increasingly being employed, inparticular, for finding relevant biomolecules which, for example, have akey role in the organism.

[0007] While very many different substances or molecules can beimmobilized on these planar chips, DNA arrays which are known todaystill suffer from problems in connection with handling andapplicability. The essential reason for these problems is the lack ofreproducibility of the overall process, which consists of manyindividual steps.

[0008] In addition, the lateral exchange of substances in the sampleliquid which has been applied to the chip is controlled solely bydiffusion, which means that there is no guarantee, at least within apracticable total period of measurement, that each species in the sampleliquid is able to interact with each sample species which is immobilizedon the chip surface.

[0009] Apart from the abovementioned planar systems, German patentapplication DE 198 28 837 A1 describes the use of hollow minicylindersas a solid phase for ELISA tests in microtiter plates. However, thispublication does not disclose any application of individual, definedspots to these hollow minicylinders.

[0010] Finally, U.S. Pat. No. 5,427,948 discloses a device forhybridizing DNA fragments, with the DNA fragments being immobilized on amembrane. The individual spots are applied to the planar membrane suchthat the preparation of the arrays and their analysis essentiallycorresponds to the methods which are known from conventional planarbiochips. The membrane is only inserted into a sealable treatment drum,which consists of two cylinders which are nested one within the other,for the purpose of implementing the actual hybridization. It is notpossible to perform an automatable process sequence using such a device.

[0011] The object of the present invention is therefore to provide animproved method, and a corresponding device, for analyzing chemical orbiological samples so as to ensure a process sequence which can bestandardized and can be fully automated. In addition, it is intendedthat the method and the device of the invention should ensure that asample volume which is to be analyzed can interact reliably with anyprobe.

[0012] This object is achieved by means of the method of the presentclaim 1 and the device of the present claim 16. The dependent claimsrelate to advantageous developments of the method according to theinvention and the device according to the invention.

[0013] The present invention accordingly relates to a method foranalyzing chemical or biological samples in which chemical or biologicalsamples and/or targets (probes) are applied, in the form of individual,defined spots, to an outer cylindrical jacket surface of a support, orare aliquoted, in the form of fluid droplets, into drill holes which arechased in the jacket surface of the support, the support is introducedinto a recess in a retainer, which recess is essentially complementaryto the cylindrical jacket surface, the samples and/or targets are actedupon chemically or physically, and the spots are then analyzed.

[0014] The core of the invention is consequently the use of a novelsupport system for investigating chemical or biological samples, whichsupport system is characterized by a cylindrical geometry, with it beingpossible to apply, for example immobilize, substances on thefunctionalized jacket surface of the cylinder or in radial drill holeswhich are chased in the cylinder jacket. Cooperation with acomplementary retainer results in an analytical system which usesclearly defined reaction volumes and which, in contrast to planarbiochips, is easily standardizable and highly automatable.

[0015] In that which follows, reference is usually made, for the sake ofsimplicity, to “spots”, with this then being able to mean, depending onthe context, either the samples which have been applied to the jacketsurface or the fluid droplets which have been introduced into the drillholes.

[0016] For example, for the purpose of applying the spots, the supportcan be conveyed, in a combined translatory and rotatory movement, past aloading device such that the spots are arranged along helical tracks onthe jacket surface. It is possible, for example, to use highly precisethreaded spindle-nut drives, which are known per se, for this purpose.Each spot can then be located unambiguously on the jacket surface or inthe drill hole. Preference is given to using a loading device which isarranged at the entrance to the retainer for applying the spots and tointroducing the support into the retainer while the spots are beingapplied such that, immediately afterward, reaction fluids can be flushedover the jacket surface. However, it is also possible to use an externalloading device and to first of all apply all the spots beforeintroducing the support into the retainer.

[0017] After that, the substances which have been applied in the spotscan be subjected to suitable chemical or physical action, for exampleDNA target spots can be hybridized with sample DNA contained in samplefluids which are led over the jacket surface and subsequently analyzed.

[0018] If, in a variant of the invention, radial drill holes whichcommunicate with a central drill hole which is provided in the supportare chased in the jacket surface, it is then possible, for the purposeof chemically and/or physically acting upon the samples or targets, tomix the fluid droplets which have been introduced into the drill holeswith a fluid which is present in the central drill hole and/or betweenthe jacket surface and the support. It is thus possible, simultaneouslyor in a chronologically staggered manner, to mix at least two differentfluids with the sample fluid droplets. A solid core can also beintroduced into the central drill hole, which core then forms a floorfor the radial drill holes which are chased in the jacket surface.

[0019] In order to analyze the spots, the support is conveyed, in acombined translatory and rotatory movement, past a detection device. Inthis connection, the direction of movement of the support isadvantageously reversed such that the support is removed from theretainer. The previously applied spots are then conveyed past thedetection device along the same helical track, thereby facilitating thestandardization and automation of the processes.

[0020] According to a particularly preferred embodiment of theinvention, target spots are introduced into at least one helicallyrecessed thread track which is chased in the jacket surface of thesupport. The targets are consequently applied, like conventional planarbiological arrays, on the surface of a support. The support is thenscrewed into the retainer, which is provided with a correspondingcounterthread, and at least one sample fluid is conveyed through achannel which is defined along the track. At the same time, thesubstances which are present in the sample fluid can interact with theprobes on the support and, in the case of DNA analyses, hybridize withthe probes, for example. A particular advantage of the method accordingto the invention, as compared with the conventional use of planar arraysis that the bolt/nut geometry which is realized by the support andretainer defines a reaction volume which is very small in cross sectionto the track. Samples and targets can therefore proceed very rapidly,even when the processes are controlled simply by diffusion, therebyenabling measuring times to be short. At the same time, transporting thesample fluid through the helical track ensures that the sample volume tobe analyzed can reliably interact with each probe. Finally, the supportis once again screwed out of the retainer and the interactions whichhave occurred between the probes and the sample fluid are detected,preferably during the unscrewing procedure.

[0021] In this connection, the sample fluid can be conveyed through thechannel by the displacement effect of the support which results onintroducing the support into the retainer. For this, and prior tointroducing the support, the sample fluid is aliquoted, either manually,using a pipetting robot or using suitable fluid ducts which areintegrated into the retainer, into the interior of the retainer, and acommunicating fluid connection is established between the channel andthe interior. However, it is also possible to use a pump to convey thesample fluid, and, where appropriate, other reaction fluids, through thechannel. It is also possible to aspirate the fluids at the end of thechannel and, where appropriate, return them to the channel entrance fora further transit.

[0022] Advantageously, the targets are immobilized in the channel of thesupport or in the radial drill holes before the samples are analyzed.Conventional techniques, which are known from planar arrays, can be usedto do this. The targets can be applied, for example, as defined spotswhen the support is being screwed into the retainer. By controlling theprocess with a computer, each probe spot is assigned to a definedposition in the thread of the retainer, which position can be referredto, when analyzing the measurement, for identifying the interactionwhich has occurred at this site between target and sample. Probe spotsare preferably immobilized on the tracks, that is, for example, thethread, in the form of a linear array. The target spots preferably havea diameter between 10 and 200 μm and are preferably applied at a lengthdensity of from 10 to 500 spots/cm, particularly preferably of from 25to 200 spots/cm.

[0023] When using a support having radial drill holes, it is alsopossible to apply highly ordered molecular monolayers on the inner wallof the drill holes. Using a method which follows the conventionalLangmuir-Blodgett technique, a liquid meniscus is allowed to penetrateinto the drill holes, whose inner wall is hydrophilic, such that theliquid is able to wet the inner wall. A monomolecular layer ofamphiphilic molecules can be formed on the surface of the liquid. Thislayer is transferred to the inner wall of the drill hole when the liquidmeniscus is withdrawn from the drill hole.

[0024] The method according to the invention is particularly suitablefor DNA hybridization or RNA hybridization. Preference is thereforegiven to immobilizing DNA/RNA targets on the support and hybridizingthem with DNA/RNA samples which are present in the sample fluid.

[0025] It is particularly advantageous, according to the invention, touse fluorescence-labeled samples, such that interactions between probesand samples, or the electrophoretic fractionation of the samples, can beanalyzed optically. For the labeling, it is possible to use anyfluorescent dyes which can be coupled chemically to the substance to belabeled. It is possible, for example, to integrate an excitation anddetection system into the retainer for this purpose.

[0026] A variant of the support system makes it possible to use thesystem in gel electrophoresis. As a result of the massive amount ofinformation contained in biological systems, DNA sequencing, inparticular, requires a highly parallel approach. DNA sequencing inshallow gel electrophoresis chambers (flat gel) having up to 100parallel analytical lanes, or, for an even higher throughput, DNAseparation in gel capillaries, having about the same degree ofparallelization but a shorter analytical time, are currently popular. Aspecial polymer solution, which effects the fractionation of theprepared DNA is used in the gel capillaries. However, the polymersolution does not permit the achievement of separation efficiencieswhich are as high as those achieved by crosslinked gels which arecustomary in the case of the flat gels. In capillary electrophoresis,the solution is removed from the capillary under pressure after theanalysis and in this way prepared for the next sequence run; crosslinkedgels can no longer be removed from the capillary.

[0027] It is now proposed, according to the invention, to use a supportin whose jacket surface several parallel, gel-coated tracks are chased,to apply the sample spots to defined regions on the tracks, to separatethe substances contained in the sample spots from each otherelectrophoretically, after the support has been introduced into theretainer, and then to detect the separated substances. The tracks can,for example, run essentially parallel to the jacket line of the support.However, they can also run helically on the jacket surface of thesupport such that a longer running distance is available with thesupport having the same external dimensions. It is also possible to makenumerous helical tracks which run in parallel, in a multihelicalarrangement. If use is made of a helical support which is designed in amultihelical manner it is then possible to make capillary tracks whichcan be cleaned automatically using a counterthread rim, such thatcapillaries can be combined with crosslinked gels, thereby combining ashort analysis time with high separation quality. Furthermore, it ispossible to achieve, in the multihelical arrangement, a high degree ofparallelization of, for example, more than 600 helical gel tracks on asupport having a radius of 1 cm. It is also possible to achieve opticalexcitation and detection in a simple manner on the cylindrical supportwhich is moved at constant rotational velocity. In this way, it ispossible to determine approximately 10 times more sequence data per unitof time than do the highest throughput appliances used in the currentstate of the art.

[0028] The present invention also relates to a device for analyzingchemical or biological samples, which device is particularly suitablefor implementing the method according to the invention. The devicecomprises a support which exhibits an essentially cylindrical jacketsurface which, on at least a part of its surface, can be functionalizedsuch that chemical or biological targets or samples can be applied, aretainer which exhibits an essentially cylindrical recess into which thesupport can be inserted, and a drive device for inserting the supportinto the retainer and for withdrawing the support from the retainer.

[0029] Advantageously, means are also provided for conveying fluidsthrough at least one channel which is defined between the jacket surfaceof the support and the inner surface of the recess. The means forconveying fluids advantageously comprise at least one fluid reservoirand one pumping device which can be used for conveying the fluid throughthe channel. According to one possibility, the means for conveyingfluids are formed by the support, acting as a piston, and the retainerrecess, serving as the fluid reservoir. For this, the support cancomprise, at its front side, a threadless cylindrical section whoseouter diameter essentially corresponds to the inner diameter of therecess in the retainer. A passage which communicates with the thread ofthe support, on the one hand, and, on the other hand, with the retainerrecess when the support is screwed in, can be chased in the threadlesscylindrical section. When the support is screwed in, the sample fluid isdisplaced out of the recess and flows through the passage into thethread channel. The means can be recovered using a sample collectingsystem at the outlet of the support and recirculated cyclically.According to a second possibility, the means are applied in an externalhose system and pumped through the helical channel using an externalpumping system. The means can be recovered at the outlet of the supportusing a sample collecting system and recirculated cyclically.

[0030] According to a variant of the device according to the invention,the constituent region of the support jacket surface which can befunctionalized can be designed as radial drill holes in the jacketsurface. These drill holes can be blind drill holes which form wells inthe jacket surface. However, the radial drill holes preferablycommunicate with a central drill hole which runs along the longitudinalaxis of the support. Defined quantities of sample fluids can beintroduced into these radial drill holes, with the sample fluids beingretained in the drill holes by capillary forces.

[0031] Means for applying the targets or samples in the form ofindividual defined spots are also advantageously provided, with it beingpossible for the means to be designed, for example, as pins which can beused to apply minimal quantities of fluid at defined sites on anappropriately functionalized surface or to introduce these quantities offluid into a functionalized drill hole.

[0032] At least one functionalizable track or drill hole is preferablychased in the jacket surface of the support. The track (or the tracks)can run essentially parallel to the jacket line of the support. In thiscase, the inner wall of the retainer can be smooth. Such a support issuitable, in particular, for electrophoretic investigations or for DNAsequencing. Subordinately, it is possible to provide a rim possessinginner teeth which, on further advancement, is able to remove thecrosslinked gels in from the tracks. However, the tracks can also runhelically on the jacket surface of the support. Using this geometricarrangement, it is possible to achieve a high channel length whichpermits a significantly larger number of laid-down targets than does aplanar surface, for example a number which is twice as high.

[0033] According to an advantageous embodiment, the helical track on thejacket surface of the support forms a thread track and the cylindricalrecess in the retainer exhibits a complementary counterthread which isdesigned such that, after the support has been screwed into theretainer, a channel, through which the sample fluid can be conveyed, isformed along the thread track. The thread track advantageously possessespossesses an essentially rectangular or trapezoidal thread profile or isdesigned as a metric ISO thread, round thread or pipe thread.

[0034] Preferably, the driving device for automatically screwing thesupport into the retainer and for unscrewing from the retainer comprisesa stepping motor, a servomotor or a synchronous motor. The motor can becoupled to the support by way of a transmission. When the supportpossesses tracks which essentially run virtually axially, it issufficient for the driving device to push the support axially into theretainer. In this case, a helical movement is only required within thecontext of the system play, depending on the thread pitch. A lineardrive or a hydraulic system can be used as the drive unit.

[0035] Advantageously, the support and/or the retainer and/or the corewhich can be introduced into a central drill hole in the support can bekept at a temperature within the range from 0° C. to 100° C.

[0036] The thread track of the support, or the internal wall of theradial drill hole, preferably exhibits a surface which is made of amaterial which is selected from the group consisting of glass, inparticular quartz glass, carbon, plastics (in particularfluorescence-poor polymer material) or resins, such aspolytetrafluoro-ethylene, polyvinylidene difluoride, polystyrene orpolycarbonate, PMMA, including membrane-forming materials, such asnitrocellulose or nylon, and also monomolecular films of amphiphilicmolecules, such as Langmuir-Blodgett films which, for reasons ofstability are preferably polymerized, metal, in particular gold,platinum, chromium or copper, semiconductor materials, such as Si, Ge,GaAs or GaP, preferably in monocrystalline form, and ceramics. Thesupports can be made of a homogeneous material; in particular plasticsare preferably used as a homogeneous material which is modified orfunctionalized throughout, such that no further surface treatment isrequired; however, the supports can also be made of composite materialsin which the surface fulfills the abovementioned criteria. Preference isgiven to surfaces which possess functional groups such as carboxyl,amino or hydroxyl groups. Particular preference is given to glasses,SiO₂ and semiconducting materials, in particular Si and modified Si. Theloading can be effected by means of flushing the surface reagents intothe sample channel and, possibly, by means of a subsequent dryingoperation, by introducing the support into a displacer-retainer.

[0037] Depending on the probe to be applied, the surface of the threadtrack of the support can additionally possess a covering layer, which ispreferably hydrophobic, or what are termed spacers and/or linkers. Theinteraction, for example the degree of mobility, between a probe and asample, for example a hybridization sample, can be affected by thelength and nature, for example the polarity, of a spacer. In thisconnection, it is advantageous to optimize the spacer with a view tomaking the probe as accessible as possible. Examples of suitable spacersare bifunctional compounds, such as diamines, diacids, for exampledicarboxylic acids, or ethylene glycol oligomers, heterobifunctionalcompounds, such as amino acids, arylacetylenes, functionalized headgroups of polymerized Langmuir-Blodgett films, lectins, biotins, avidinsor streptavidins or combinations thereof. Spacers can also besynthesized from several moieties which are linked to each other bymeans of covalent and/or noncovalent bonds. Examples of covalentlylinkable moieties of a spacer are heterobifunctional elements, such asamino acids, for example 6-amino-capric acid or [lacuna]-aminobutyricacid, several of which can be bonded to each other for the purpose ofelongating a spacer. Examples of moieties of a spacer which can belinked noncovalently are molecules between which it is possible to formaffinity bonds, as between biotin and avidin or streptavidin or theiranalogs, or between DIG and anti-DIG. Spacers can possess one or morebinding sites for the probes which are to be applied. As a rule, theabove-discussed hetero-bifunctional elements possess one such bindingsite for oligonucleotide probes, for example, whereas molecules whichform affinity bonds, such as avidin or streptavidin, possess severalbinding sites. The latter molecules can lead to an advantageous increasein the immobilized probes per unit area. Spacers can also possessvariable binding sites which offer different bonding possibilitiesdepending on configuration. This applies, in particular, to affinitybonds, whose binding affinity can vary depending on the configuration ofthe participating binding partners.

[0038] Bonds between the surface of the support and the probes, forexample polynucleotide targets, can be covalent or noncovalent (forexample electrostatic or coordinate). Covalent bonds are preferred.Frequently, the probes or spacers are not bound directly to thefunctional groups which may possibly be naturally present on thesurface. In these cases, the functional groups which are present arefirst of all modified, for example by introducing a more expedientfunctional group. The skilled person is familiar with methods which aresuitable for this purpose, depending on the surface material and thedesired bond. Glassy surfaces of supports according to the invention arepreferably functionalized by forming siloxane bonds. In this connection,silanes, for example compounds possessing trichlorosilyl ortrisalkoxysilyl groups, are bonded to the hydroxyl groups, which arenaturally present, of the Si—OH functionalities. The probes or spacers,for their part, are bonded to more expedient functional groups which areprovided by the silanes. Epoxy groups can be introduced, for example,using 3′-glycidoxy-propyltrimethoxysilane and amino groups can beintroduced, for example, using aminopropyltriethoxy-silane. Diepoxidesor cyanogen bromide can likewise be used for functionalizing thesurface. In the same way, the formation of acetal from alcohols usingaldehydes or ketones, such as the formation of thioacetal, oriodothiophosphate bonding, can be used for the covalent bond.

[0039] On the other hand, probes or spacers can be bound, without anyfurther functionalization, to some surfaces, in particular to specialpolymers. These include, for example, polyvinylidene difluoridepossessing aminopropyl groups, or particular Langmuir-Blodgett films inwhich the head groups can even function as spacers.

[0040] It is also possible to apply what are termed multicoatings, i.e.several different layers, to the support.

[0041] In addition, the surface of the support material and/or thecoatings can be modified by physical methods such as plasma treatment orsputtering.

[0042] Advantageously, the retainer additionally possesses an excitationand detection device for investigating the chemical or biological probesor samples. The excitation and detection device is preferably arrangedbetween the drive unit and the retainer, such that the tracks, or thesingle helical track, can be analyzed when rotating the support out ofthe retainer.

[0043] In the case of electrophoretic measurements, the screw device isarranged vertically; in this case, the excitation and detection unit isarranged in the lower region of the retainer. The samples are thenapplied at the upper end of the support and migrate downward in a gelalong an electrical potential gradient. In this case, the detectionsystem records the migration time of the individual bands. Theindividual channels or tracks can be investigated sequentially byrotating the support in the retainer.

[0044] Preference is given to using optical investigation methods, withchemiluminescence measurements or fluorescence measurements beingpreferred. For the fluorescence measurement, the fluorescence-labeledsamples are advantageously excited with a focused laser beam and theemitted fluorescent light is detected using a photomultiplier or aphotodiode. The excitation and/or detection can take place confocally inorder to fade out interfering fluorescent light from the solution in thechannel or from the support. If different fluorescent labels are used,the detection can also take place spectrally or in a time-resolvedmanner such that it is possible to draw conclusions with regard to theindividual constituents of the bound labels. If a complete integrationof an excitation and detection system into the retainer is notdesirable, it is also possible to use fiber optics in order to conductlight from and to an external detection system. The device according tothe invention therefore preferably possesses an excitation and detectionarrangement which comprises means for simultaneously emitting light ofdiffering wavelength and means for simultaneously detecting light ofdiffering wavelengths and/or for detecting optical signals in atime-resolved manner. The variant of the device according to theinvention in which the support is provided with radial, functionalizabledrill holes is also particularly suitable for carrying out absorptionmeasurements. For example, light can be conducted, by way of the centraldrill holes, into the individual radial drill holes and onto a detectorwhich is arranged outside the cylindrical jacket of the support.

[0045] The present invention finally also relates to the use of thedevice according to the invention for analyzing DNA or RNA, with thebiological probes or samples to be immobilized being selected from thegroup comprising DNA, RNA, cDNA, oligonucleotides or PNA oligos.

[0046] In this connection, a preferred use is directed toward screeningor quantifying samples for particular ligands (target sequences) whichbind with high affinity to immobilized oligonucleotides/polynucleotidesor synthetic analogs, cDNA, ccDNA or cRNA. For this, a solutioncontaining labeled samples is conveyed through the channel along thehelical track of the support. Unbound ligand is removed by rinsing thechannel. Ligands which have bound to the immobilized probes as a resultof adequate affinity are detected when unscrewing the support from theretainer.

[0047] Hybridization to DNA spots containing immobilizedoligonucleotides/polynucleotides or synthetic analogs, cDNA, ccDNA orcRNA, where appropriate with subsequent primer extension, for thepurpose of sequencing, gene expression analysis, typing viruses andmicroorganisms, and mutation analysis, are also regarded as beingpreferred uses.

[0048] Samples can be obtained in a conventional manner. Usually, atleast parts of nucleic acids of interest are isolated from a tissuesample. In the case of genomic investigations carried out on eukaryotes,any tissue is suitable provided it contains cell nuclei. Blood,lymphocytes derived from peripheral blood or a buffy coat, skin, hair orsemen are common sample sources from which both DNA and RNA can beisolated. Body fluids, such as serum, sputum, urine, peritoneal fluid,pleural fluid or bronchoalveolar lavage are suitable for isolatingnucleic acids from viruses, bacteria or fungi. On the other hand, mRNAcan only be isolated from those cells or tissues in which the desiredmRNA is transcribed.

[0049] The skilled person is familiar with a large number of methods forisolating nucleic acids. Only a few will be briefly outlined here by wayof example.

[0050] In order to isolate genomic DNA, the cells can be lysed, forexample under the action of detergents and/or proteinases, proteins canbe removed and the DNA can be isolated, for example by precipitatingwith known organic solvents. It may also be appropriate to carry out achromatographic separation, for example using commercially availablespin columns. Similar methodological procedures are used when isolatingtotal RNA. Polyadenylated mRNA can in turn be isolated from this totalRNA by using systems which are based on oligo-(dT). Expert knowledgewill determine the choice of an expedient protocol. RNA can then betranscribed into cDNA by means of reverse transcription. DNA or cDNA canbe amplified using various methods which are known to the skilledperson.

[0051] The complexity of a sample, i.e. the diversity and sequencelength of the nucleic acids present in it, can be decreased, prior tothe investigation, by enriching those nucleic acids which contain thetargets. If a subset of mRNA is to be investigated, it is possible, forexample, to hybridize the total mRNA with the immobilized nucleic acidpolymers, then to treat with RNase A in order to digest single-strandedregions, and subsequently to denature the double-stranded hybrids, inorder, finally, to remove the nucleic acid polymers, such that therethen remains a pool of mRNA whose complementarity to the immobilizednucleic acid polymers has been increased. The skilled person is familiarwith other methods which serve the same purpose and which can be usedwithin the context of the present invention, such as digestingdouble-stranded nucleic acids with RNase H using suitable hybridizationprobes.

[0052] In addition, the device according to the invention can be usedfor protein analysis and for drug screening, with the biological probesor samples in this case comprising proteins, in particular antibodies,receptors or ligands. It is likewise possible to use the deviceaccording to the invention for allergy diagnosis, with the biological orchemical samples in this case being selected from the group comprisingantigens, haptens or allergens.

[0053] Finally, the present invention relates to the use of the deviceaccording to the invention as a DNA computer. It has already beendemonstrated that oligonucleotides which are immobilized on the surfaceof a support, for example by specifically hybridizing with particularsamples or as a result of specific enzymic digestion, can be used forsolving mathematical problems. Reference may be made, at this point, byway of example, to the review article by L. M. Adleman “Computing withDNA”, Scientific American 279(2): 54-61, 1998. Special applications aredescribed, for example, in Liu et al., “Progress toward demonstration ofa surface based DNA computation: a one word approach to solve a modelsatisfiability problem”, Biosystems 51(1-3): 25-33, 1999 or Smith etal., “A surface based approach to DNA computation”, Journal ofComputational Biology, 5(2): 255-267, 1998. A large number of themethods which are described there can also be implemented using a linearoligonucleotide/polynucleotide array on a cylindrical or helical supportof the device according to the invention.

[0054] The present invention is described in more detail below whilereferring to the implementation examples which are depicted in theattached drawings.

[0055] In the drawings:

[0056]FIG. 1 shows a first embodiment of a device according to theinvention;

[0057]FIG. 2 shows a second embodiment of a device according to theinvention;

[0058]FIG. 3 shows a third embodiment of a device according to theinvention;

[0059]FIG. 4 shows an enlarged cutout depiction of the application ofthe probes in the device in FIG. 3;

[0060]FIG. 5 shows a third embodiment of a device according to theinvention which is particularly suitable for electrophoreticinvestigations;

[0061]FIG. 6 shows a view from above onto the device shown in FIG. 5;

[0062]FIG. 7 shows a variant of a support for electrophoreticinvestigations, seen from above;

[0063]FIG. 8 shows the support shown in FIG. 7 in side view;

[0064]FIG. 9 shows another variant of a support for electrophoreticinvestigations seen from above;

[0065]FIG. 10 shows the support shown in FIG. 9 in side view;

[0066]FIG. 11 shows another variant of a support of the device accordingto the invention;

[0067]FIG. 12 shows a view from above onto the support shown in FIG. 11;

[0068]FIG. 13 shows a detailed cutout of the support shown in FIG. 11,which is arranged in a complementary retainer; and

[0069]FIG. 14 shows a variant of the support shown in FIG. 11 in acorresponding retainer.

[0070]FIG. 1 shows a device according to the invention for analyzingchemical or biological samples, which device is designated in itsentirety by the reference number 10. The device 10 exhibits a support 11having a cylindrical jacket surface 12. The jacket surface 12 isfunctionalized such that chemical or biological targets can be appliedand immobilized using a loading device 13, as depicted in more detail inFIG. 4. The loading device 13 can, for example, be a small tube having atapering tip, which device has a reservoir from which substances whichact as probes, and which are customarily dissolved, dispersed oremulsified in a liquid, can be transferred to the functionalizedsurface, for example by way of capillary forces. The loading device 13can, for example, be fixed on a rotatable and/or displaceable arm 14 andmoved in the direction of the jacket surface 12 by means of an advancingarrangement 15.

[0071] A spindle 16 of a linear drive 17 (as is marketed, for example,by Haydon Switch and Instrument, Inc.) is connected to the support 11such that this latter can be set in a combined rotatory and translatorymovement. In this movement, the loading device 13 can be used to applyspots 18 along a helical track 19 on the jacket surface 11.

[0072] The device 10 according to the invention additionally comprises aretainer 20 which exhibits an essentially cylindrical recess 21 overwhich the support 11 can be positioned using a robot arm (not depicted).The support 11 is inserted into the retainer 20 using the drive 17. Asample liquid and, where appropriate, other reaction liquids, are thenconveyed through an annular channel which is defined between the jacketsurface 11 and the inner wall of the recess 21. Sucking-off arrangements(not depicted here), which lead away the sample liquid after it hasflowed through the annular channel, can be provided in the upper regionof the retainer 20.

[0073] The interaction of the target spots 18, which are immobilized onthe jacket surface 11, and the substances in the sample liquid can bedetected when withdrawing the support 11. An excitation and detectiondevice 22, which is depicted diagrammatically in FIG. 1, is provided forthis purpose in the upper region of the retainer 20. The support 11 iswithdrawn by the drive 17 once again in a combined translatory androtatory movement such that all the spots 18 on the track 19 areconveyed past the detection device 22.

[0074] Advantageously, the support 11 and/or the retainer 20 can beheated and cooled. Preference is given to being able to set atemperature of from 10° C. to more than 95° C., such that the device canalso be used for carrying out amplification reactions, for example PCR.

[0075]FIG. 2 shows a second embodiment of a device 10 according to theinvention. Elements which have already been explained in connection withthe embodiment shown in FIG. 1, or which exert a similar function, aredenoted by the same reference numbers.

[0076] The device shown in FIG. 2 exhibits a cylindrical, helicallyshaped support 11 which is provided with an outer thread 23 on a part ofits length. The helical thread track 19 of the support 11 exhibits afunctionalized surface on which chemical or biological probes can beapplied and immobilized using a loading device 13. The loading device 13exhibits a tapering tip 24. The device 10 according to the inventiononce again includes a retainer 20 which exhibits an essentiallycylindrical recess 21 which is provided with an inner thread 25 which iscomplementary to the outer thread 23 of the support 11. The flank depthsof the inner thread 25 and of the outer thread 23 are selected suchthat, when the support 11 has been screwed in, a helical channel 26 isdefined. A sample liquid, which can interact with the probes which areimmobilized in the thread track 19, can be conveyed through the channel26.

[0077] The device according to the invention exhibits means forconveying fluids, for the purpose of conveying the sample liquid and,where appropriate, other reaction liquids through the channel 26. In thecase of the embodiment depicted in FIG. 2, the sample liquid isaliquoted into the recess 21 of the retainer 20. This can be effectedby, for example, filling the recess 21 above the screwing-in aperture ofthe retainer 20 before the support 11 is screwed in. However, this canalso be effected by means of a fluid duct 28 which opens out into therecess 17 in the region of the floor 27 of the retainer 16. The fluidduct is advantageously provided with a nonreturn valve 29 which preventsthe sample liquid which is present in the recess 21 being displaced intothe duct 28 when the support 11 is screwed in. The support 11 is nowextended, in its lower region, by a displacement piston 29 which issealed off toward the recess 21 by a sealing lip 30. If the outerdiameter of the displacement piston 29 essentially corresponds to theinner diameter of the recess 21, it is also possible, when suitablematerials are selected, to dispense with a sealing lip. A passage 31,whose one end opens out by way of an aperture 32 in the bottom region ofthe displacement piston 29 or the sealing lip 30 and whose other endopens out by way of an aperture 33 into the thread track 29 of the outerthread 23 of the support 11, is chased in the displacement piston. Thereis therefore a communicating connection between the thread track 19 andthe recess 21 when the support is screwed in. Screwing in the support 11presses the sample liquid out of the recess 21 and through the passage31 and, after it has flowed out of the aperture 33, conveys it throughthe thread track 19. This consequently ensures that the sample liquid isable to come into contact with every target spot which is immobilized inthe thread track 19.

[0078] Sucking-off arrangements (not shown here), which lead away thesample liquid after it has flowed through the thread track, can onceagain be provided in the upper region of the retainer 20.

[0079] The interaction of the probes which are immobilized in the threadtrack 19 and the substances in the sample liquid can be detected whenscrewing out the support 11. In this embodiment, an excitation anddetection device 22, which is depicted diagrammatically and which inthis case is integrated into the retainer, is provided for this purposein the upper region of the retainer 20.

[0080] The support 11 is advantageously screwed in and screwed outautomatically using a drive device 17 which can set the support 11 inrotation in both rotational directions, for example by way of a spindle16.

[0081] As intimated in the diagram shown in FIG. 2, the retainer 20 canbe constructed in a modular manner. For example, the retainer canexhibit an outer jacket 34 in which temperature-controlling devices are,for example, arranged. An inner jacket 35, which exhibits an innerthread which is specific for particular supports, is inserted into theouter jacket. In the same way, the retainer can exhibit aninterchangeable bottom plate 36 such that it is possible to constructsystems with and without fluid ducts or with one or more fluid ducts.The loading device 13 and the detection device 22 are alsoadvantageously constructed in a modular manner.

[0082]FIG. 3 depicts a third embodiment of the device 10 according tothe invention. In the embodiment shown in FIG. 3, the helically shapedsupport 11 is not used for displacing the sample liquid; instead, thesupport 11, which is coated with immobilized probes, is initiallyscrewed completely into the retainer 20. When the support has beenscrewed in, a fluid duct 37 which has been chased in the bottom regionof the retainer 20 communicates with the thread track 19. In addition,the embodiment provides a withdrawal duct 38 through which fluid can bepumped off from a collecting region 40 by way of a pump 39 and can beconveyed back by way of the duct 37. The retainer is sealed off in theupper region 41. A three-way valve 42 enables sample fluid to be fed infrom a reservoir 43.

[0083]FIG. 4 depicts a preferred variant of the loading of the targetspots 18 into the thread track 19 of the support 11 in more detail. Afluid which contains substances which are being used as probes is firstof all aspirated from a (not depicted) storage container into a channel44 of the small capillary tube 13. The fluid is applied, in the form ofminimally sized droplets, by way of the tip 24 to the functionalizedthread 19 in order to form individual spots 18 on this thread.

[0084] However, the spots can also be loaded without any contact. Forthis, the small capillary tube is, for example, brought close to thethread without, however contacting it and delivers individual drops ofthe probe liquid by means of brief pressure surges. These pressuresurges can, for example, be generated piezo-electrically.

[0085] Alternatively, the probes can also be introduced into the helicaltrack in the form of with beads on which the probes are immobilized. Inthis connection, the beads, which typically have a diameter of from 1 μmto 1 mm, can be adhered in the thread or be clamped between the flanksof the thread.

[0086]FIGS. 5 and 6 depict a preferred variant of the support 11 whichis suitable, in particular, for carrying out electrophoretic separation.FIG. 6 shows a cross section along the line VI-VI in FIG. 5. The deviceexhibits reservoirs 50, 51 for a buffer solution and a radial packingring 52 for sealing off between the support 11 and the retainer 20. Thesamples which are to be separated electrophoretically are applied asspots, at one end of the support 11, to the tracks 19, which are, forexample, filled with a gel, of the support 11. A high electrical voltageis applied, parallel to the longitudinal axis of the support 11, betweenthe buffer reservoirs 50, 51 using electrodes 52, 54, which are showndiagrammatically in FIG. 5. As a result of having different chargesand/or different mobilities, the individual constituents in the samplesare separated in the gel such that they arrive at the other end of thesupport 11, for example at the level of the line 55, in achronologically staggered manner and can be detected by a detectiondevice 22. When a detection device, which is designed for opticallydetecting the sample constituents, is arranged outside the retainer 20,the retainer 20 can, in this region, exhibit a transparent window or anarrow slit. A ring 57 having an inner thread can be arranged on acommon base plate 56 over a recess (which is not depicted here) in thebase plate in order to remove the gel once again, after theelectrophoresis, from the tracks 19 of the support 11. The arrows 58 and59 indicate that the support 11 and the base plate 56 can be moved inrelation to each other using positioning elements which are known per se(but which are not shown here) such that the support 11 can also bescrewed automatically into the ring 57 after the electrophoresis hascome to an end. In the variant depicted in FIGS. 5 and 6, two tracks 19are provided on the support, which tracks run in a spiral path having arelatively large pitch. In this case, the inner wall of the cylindricalretainer 20 does not need to exhibit a complementary thread but can alsobe smooth in form instead.

[0087] Other variants of the support are depicted in FIGS. 7-10.

[0088]FIG. 7 shows a view from above and FIG. 8 shows a side view ofanother embodiment of the support 11. In this case, the tracks 19 areessentially arranged parallel to the longitudinal axis of the support11. The flanks which bound the tracks laterally define a cylinder jacket12 of the support such that the tracks 19 as it were constitutedepressions in the cylindrical support 11. The support 11 can than beinserted into a retainer (not depicted here) which, like the retainershown in FIG. 5, is provided with electrodes above and below thesupport. In this case, too, the retainer can exhibit a cylindrical innerspace having smooth side walls. There is no need for an inner thread.After the support has been inserted into the retainer, the sample whichis to be separated electrophoretically is loaded onto the upper end ofthe tracks 19 and a voltage is applied. The samples which are separatedon the tracks 19 are then detected in the lower region of the retainer(as indicated by the broken line). Detection is therefore once againeffected by measuring differences in the migration times of theindividual constituents of the sample on the electrophoresis tracks.During the measurement, the support can be rotated about itslongitudinal axis in order to analyze the individual tracks one afterthe other.

[0089]FIGS. 9 and 10 show a variant of the support shown in FIGS. 7 and8 in which the tracks 19 are inclined relative to the longitudinal axisof the support. In this way, it is possible to increase theelectrophoretically utilizable migration distance of the individualtracks 19 without the overall measurements of the system beingincreased.

[0090] FIGS. 11 to 14 depict another variant of the support 11 of thedevice according to the invention for analyzing chemical or biologicalsamples. Once again, the support 11 possesses a general form which ishelical in shape and in which individual sample spots are distributedalong a helical thread track 19. In contrast to the previous examples,the sample spots are not applied to the basal surface of the threadtrack 19. Instead, the support 11 exhibits drill holes 61 in the threadtrack 19, which drill holes 61 are orientated radially to thelongitudinal axis 60 of the support 11 and open out into a central drillhole 62 which is chased along the longitudinal axis 60. The radial drillholes 61 therefore constitute a communicating connection between thethread 19 and the central drill hole 62 as can be seen, in particular,from the detail view shown in FIG. 13. The diameter of the drill holes61 is preferably in the range from 1 μm to 1 000 μm and veryparticularly preferably in the range of 50-200 μm. The length of thedrill holes 61, which are not depicted true to scale in the drawing, istypically in the millimeter range.

[0091] Suitable capillary needles or similar loading devices can be usedto fill the individual drill holes 61 individually with a sample fluid,which is retained in the drill holes by means of capillary forces. Thedroplets 63 of sample fluid which are present in each drill hole 61 canbe brought into contact, and mixed, with other fluids by way of thethread track 19 and/or the central drill hole 62. Depending on thequantity of the sample fluid 63 which has been metered in to theindividual drill holes, an air cushion 66 or 67, respectively, whichinitially prevents the fluids being mixed, is formed between the fluid64 which is present in the thread 19 and the fluid 65 which is presentin the central drill hole 62. A sequential mixing of the sample fluid 63with the fluids 64 and 65, respectively, can be brought about at definedtimes in dependence on the regulation of the pressure difference in thefluids in the central drill hole 62 and in the thread 19, respectively.In the diagram shown in FIG. 13, the contact angles of the fluids aredepicted such as corresponds, for example, to an aqueous fluid in ahydrophobized drill hole 61.

[0092]FIG. 14 depicts an exemplary arrangement of a variant of thesupport 11 shown in FIG. 11 in a retainer 20. It is also demonstrated,in the embodiment shown in FIG. 14, that the support 11 is particularlysuitable for absorption measurements. For this, an optical waveguide 68,which, on a level with a detector 69 which is integrated into theretainer 20, exhibits an angled facet which radiates light radially inthe direction of the detector 69, can, for example, be introduced intothe central drill hole 62. If the individual drill holes 61 allow thisradial light beam to pass through, absorption measurements can becarried out on the fluid which is present in the drill hole. The deviceshown in FIG. 14 also demonstrates that the retainer 11 can be providedwith a conically shaped stopper 70 which is designed to be complementaryto the upper edge 71 of the retainer 20 and which seals this edge whenthe support is screwed in. It is naturally possible for the retainer 20to be sealed in this way in the embodiments of the device according tothe invention which have previously been described with reference toFIGS. 1-10.

[0093] The stopper stopper 70 can also be designed as a radial packingring which can be connected to the retainer 20 by way of a union nut ora thread, for example, and in which the shaft of the support 11 isfreely rotatable such that, with the retainer being tightly sealed, thesupport 11 can move past the detector 69. In order to prevent variationsin pressure in the liquid in the complementary thread of the retainer 20when the support 11 moves, the retainer 20 can exhibit, in its upperregion, an outlet 72 which is linked, by way of an equalizer 73, with aninlet 74 in the lower region of the retainer. The lower region of theretainer 20 is then once again designed as a radial packing ring 75.

[0094] The embodiment of the device according to the invention as shownin FIGS. 11-14 is suitable, in particular, for stopped-flow experimentswith a high degree of time resolution and a high degree of sampling. Inthis case, it is possible, for example, to introduce identical samplesinto the drill holes 61 and to start a reaction by applying pressure ata defined point in time. Since the reaction begins at the same time inall the drill holes 61, a sequential analysis of the individual drillholes (for example on rotating the support 11 out of the retainer 20),constitutes a time-resolved measurement of the reaction kinetics. In thesame way, it is possible to carry out highly parallel stopped-flowexperiments, for example when different samples are introduced into theindividual drill holes.

[0095] The device according to the invention is also particularlysuitable for carrying out mixing assays using two or more differentreaction solutions.

[0096] It is also possible to carry out what are termed hot-startexperiments by isochronously mixing using the air cushions which areexpelled by pressure pulses.

[0097] Another preferred area of application for the device shown inFIGS. 11-14 is in the area of what are termed flush-through assays orflush-through arrays. It is possible to increase the sensitivity inexperiments of this nature by immobilizing a relatively large quantityof sample on the inner wall of the drill holes 61 and having a sensitivedetection, by means of having a long detection path in the drill hole inthe case of absorption measurements, for example.

[0098] In the case of the support shown in FIG. 11, the central drillhole can also be sealed using a slide-in core (not shown in thedrawings) such that the support 11 is designed as a type of microtiterplate (or submicrotiter plate) having helically arranged wells. In thiscase, the outer diameter of the (where appropriate heatable) coreessentially corresponds to the inner diameter of the drill hole 62. Thecore can naturally also have a somewhat smaller diameter such that thecentral drill hole 62 does not have to be completely filled with fluidbut only has to be filled in a narrow ring (not shown in the drawings)[lacuna] core and the inner wall of the drill hole 62.

[0099] Since a rapid and efficient change in temperature in the threadtrack 19 and the radial drill holes 61 can be achieved by a change ofmedium within the central drill hole 62, specific loading of the drillholes 61 also makes it possible to carry out a highly parallel, rapidand effective PCR (polymerase chain reaction). For this, the PCRreaction mix is introduced into the wells by way of the central drillhole 52, or the central channel, which is constituted such that it cancontain from a few microliters, or even less, up to several milliliters.In a conventional PCR, this PCR reaction mix consists of buffersolution, DNA polymerase, a set of DNA primers and the dNTPs which arerequired for synthesizing the counterstrands. In the case ofquantitative PCR (Taq Man®, trademark belonging to the company AppliedBiosystems, Foster City, Calif.), use is made of a special primer paireach member of which carries a different dye label which exhibitsfluorescence characteristics in solution or in the annealing phase whichdiffer from those after strand duplication, thereby providinginformation on the progress of the PCR. A simpler principle is that ofusing intercalation dyes to detect the products resulting from the PCRdirectly. The status of the PCR is registered simply by measuring thefluorescence intensity. The template DNA, that is the sequence which isin each case to be amplified, is supplied by pipetting it into the drillholes 61 which are filled with PCR solution and subsequently reducingthe pressure in the central drill hole in order to retract the PCRmixture into the well. After liquid (e.g. deionized water) has beenpumped through, this thereby encloses an air bubble, which prevents anydilution or contamination of the PCR mixture in the thread channel, inthe thread channel 19 at the end of the drill hole 21 toward the threadtrack. The temperature cycling can now begin. For quantitative PCR, thewells are conveyed, after each cycle, past a fluorescence detector whichis integrated into the retainer 22 and the instantaneous fluorescenceintensity is measured and stored. Short pulses by way of the centralliquid can be used to increase blending and, possibly, shortenreactivity or reaction times. For preparative purposes, the amplifiedDNA solution can be removed after the liquid in the thread has beenpumped off and the screw has been withdrawn from the retainer.

[0100] Although a support having a central drill hole 62 and radialdrill holes 61 has only been presented here for the case of a helicallyshaped support 11, it will be understood that, in principle, thepreviously presented variants of the support 11, for example those shownin FIGS. 5-9, can also be provided with radial drill holes, which openout into a central drill hole, instead of with the spots 18.

[0101] In that which follows, an application example which can becarried out in all the embodiments of the device according to theinvention is explained in more detail.

EXAMPLE Hybridizing DNA Arrays

[0102] System Parameters:

[0103] With a selected support radius of 5 mm and a channel width of 50μm and the thread pitch being 0.1, 32 mm of channel length are obtainedper revolution. 320 targets can be introduced into such a channel perrevolution, giving 32 000 spots in the case of a thread bar of 1centimeter in length. The customary length is several centimeters, whichmeans that several hundred thousand samples can be deposited. The spotlength density is 20 per centimeter of the channel. With a customarychannel height of 10 μm, the channel volume becomes 15 μl per centimeterof channel length.

[0104] Preparing the System, Hybridizing and Reading the Fluorescence:

[0105] The support is inserted into the retainer. The support-retainerthread system is flushed with degassed, double-distilled [lacuna] whichhas been sterilized by filtration. It is then rewashed with a 70%-30%ethanol-water solution in order to remove microbubbles of gas and toachieve sterility. After that, coupling reagents are flushed through thechannel, thereby functionalizing the channel in correspondence with thesupport material. Nitrocellulose methanol solution (NC solution) can beused as an all-purpose reagent. After the NC solution has been passedthrough, the support is withdrawn from the retainer. In connection withthis, a suitable pin can be inserted into the channel track in order togenerate a defined loading thickness. After the tracks have dried, theDNA targets are loaded (spotting) as the support is being inserted. Atpresent, the solid pin technology is being used for this purpose. Forthis, use is made of several pins which are arranged in a row. The pinsare located at an interval of approx. 4.5 millimeters, which interval ismatched to the particular channel distance so as to ensure problem-freeinsertion into the channel track. If the support seals off the retainertightly after insertion, 100% ethanol is then conducted in. After that,the ethanol is displaced with buffer solution thereby making it possibleto introduce buffer in a bubble-free manner. A start is now made insetting the temperature of the support-retainer system; in thisconnection, temperatures are set in the range of 20-68° C. depending onthe length of the DNA target. Probe DNA is now pumped in and, inconnection with this, hybridized (see under A. and B.).

[0106] After the hybridization, washing with buffer takes place onceagain and, after that, the support is withdrawn from the retainer. Asthis is being done, the channel track is read using a fixed,ultrasensitive fluorescence detection system and the results arerecorded by a data system. For the purposes of analytical certainty,several, as a rule two, spots of a target sequence are loaded on, whichspots [lacuna] loaded at a variable distance which is known to theevaluation algorithm. On being analyzed, the spots are compared withidentical DNA and the quality and reproducibility of the hybridizationthereby tested. If the quality is not in a predetermined range, thisspot is then banned from any further evaluation. In this way, high dataquality is achieved selectively.

[0107] In order to make the support ready for a fresh cycle of analysis,the support is inserted into the retainer and flushed with a cleaningsolution (bleach). It is then washed with water and buffer and the pH ismeasured. If necessary, the channel track can also be cleanedmechanically using a pin. For safety, the channel track is also scannedoptically by the detection system, and the quality of the channel trackestablished, before a fresh analytical procedure is carried out;depending on the circumstances, a fresh cleaning cycle may be necessary.

[0108] A. Probe Labeling

[0109] Total RNA was prepared (Chomczynski P. and Sacchi N, Anal.Biochem. 1987 162(1), 156-159) and used for isolating poly(A) RNA withthe aid of (oligo-dT)-Dynabeads (Dynal AS, Oslo, Norway) in accordancewith the manufacturer's instructions. For primer annealing, 2 μg of theresulting poly(A) RNA, together with 6 μl of oligo(dT)₂₁ (50 μmol/l; ARKScientific Biosystems GmbH, Darmstadt), were made up to 15 μl withDEPC-treated water, after which this mixture was heated at 70° C. for 5min and then cooled on ice. 6 μl of 5× first strand buffer (LifeTechnologies GmbH, Karlsruhe; 250 mmol of Tris-HCl/l, pH 8.3; 375 mmolof KCl/l; 15 mmol of MgCl₂/l), 1 μl of RNase inhibitor (Roche MolecularBiochemicals, Mannheim), 100 mmol of dithio-threitol (Life TechnologiesGmbH, Karlsruhe), 0.6 μl of 50× dNTP-T (in each case 25 mmol/l dATP,dCTP and dGTP; 10 mmol of dTTP/l; Roche Molecular Biochemicals,Mannheim), 2 μl of Cy3-dUTP or Cy5-dUTP (1 mmol/l; Amersham-PharmaciaBiotech Europe GmbH, Freiburg) and 2 μl of Superscript II (200 units/μl;Life Technologies GmbH, Karlsruhe) were then added. Thefluorescence-labeled first-strand cDNA was then synthesized at 42° C.for 2 hrs in a preheated Thermocycler. In order to denature the RNA, 2.5μl of 1N NaOH were added and the mixture was heated at 65° C. for 10min. After it had been cooled down on ice, it was neutralized with 6.2μl of 1 mol/l Tris-HCl, pH 7.5, diluted with TE buffer (10 mmol ofTris-HCl/l, 1 mmol of EDTA/l, pH 8.0) to 400 μl and concentrated down ona Microcon-30 column (Millipore GmbH, Eschborn; centrifugation at 13 000rpm for 10 min) to 10 μl.

[0110] B. Hybridizing

[0111] For the hybridization, 5 μl each of Cy 3-labeled cDNA and Cy5-labeled cDNA were mixed with each other and then treated with 50 μl ofhybridization buffer (0.25×SSC, 0.02% SDS, 1% N-lauroylsarcosine, 1%blocking reagent (Roche Molecular Biochemicals, Mannheim), 1 μg of humanC_(ot)1 DNA (Life Technologies GmbH, Karlsruhe)). This hybridizationsolution was denatured at 95° C. for 2 min in the Thermocycler, afterwhich the temperature was reduced to 50° C. and hybridization wascarried out for 14 hrs. The hybridization solution was removed and thetubes were washed 3×5 min at room temperature with 2×SSC/0.1% SDS,followed by 3×5 min with 0.2×SSC/0.1% SDS at 42° C. and, in conclusion,1×5 min with 0.1×SSC/0.1% SDS at 42° C.

1. A method for analyzing chemical or biological samples, whichcomprises chemical or biological samples and/or targets being applied,in the form of individual, defined spots, to an outer, cylindricaljacket surface of a support, or being aliquoted, in the form of fluiddroplets, into drill holes which are chased in the jacket surface of thesupport, the support being inserted into a recess in a retainer, whichrecess is essentially complementary to the cylindrical jacket surface,the samples and/or targets being acted upon chemically or physically andthe spots then being analyzed.
 2. The method as claimed in claim 1, inwhich the drill holes which are chased in the jacket surface communicatewith a central drill hole which is provided in the support, wherein, forthe purpose of chemically and/or physically acting upon the samples ortargets, the fluid droplets which have been introduced into the drillholes are mixed with a fluid which is present in the central drill holeand/or between the jacket surface and the support.
 3. The method asclaimed in claim 1 or 2, wherein, for the purpose of applying the spots,the support is conveyed, in a combined translatory and rotatorymovement, past a loading device such that the spots are arranged alonghelical tracks on the jacket surface.
 4. The method as claimed in claim1 or 2, wherein the support is introduced into the retainer while thespots are being applied.
 5. The method as claimed in claim 3 or 4,wherein, in order to analyze the spots, the support is conveyed, in acombined translatory and rotatory movement, past a detection device. 6.The method as claimed in claim 5, wherein the support is removed fromthe retainer while the spots are being analyzed.
 7. The method asclaimed in one of claims 1 to 6, wherein the spots are introduced into ahelically recessed thread track on the support.
 8. The method as claimedin claim 7, wherein the support is screwed into the retainer, which isprovided with a corresponding counterthread, and target spots areapplied at the same time, at least one sample fluid is conveyed througha channel which is defined along the track, the support is once againscrewed out of the retainer and interactions between the target spotsand the sample fluid are detected at the same time.
 9. The method asclaimed in claim 8, wherein the sample fluid is conveyed through thechannel by a displacement effect of the support.
 10. The method asclaimed in one of claims 1 to 9, wherein the targets are immobilized onthe jacket surface of the support or in the drill holes.
 11. The methodas claimed in claim 10, wherein DNA or RNA targets are immobilized onthe support and hybridized with the DNA or RNA samples which are presentin the sample fluid.
 12. The method as claimed in one of claims 1 to 11,wherein fluorescence-labeled samples are used.
 13. The method as claimedin claim 1, wherein use is made of a support in whose jacket surfaceseveral parallel, gel-coated tracks are chased, the sample spots areapplied to defined regions on the tracks, the substances contained inthe sample spots are separated from each other electrophoretically afterthe support has been introduced into the retainer, and the separatedsubstances are subsequently detected.
 14. The method as claimed in claim13, wherein the tracks run essentially parallel to the jacket line ofthe support.
 15. The method as claimed in claim 13, wherein the tracksrun helically on the jacket surface of the support.
 16. A device foranalyzing chemical or biological samples, in particular for implementingthe method as claimed in one of claims 1 to 15, comprising a supportwhich exhibits an essentially cylindrical jacket surface which, on atleast a part of its surface, can be functionalized such that chemical orbiological targets or samples can be applied, a retainer which exhibitsan essentially cylindrical recess into which the support can beinserted, and a drive device for inserting the support into the retainerand for withdrawing the support from the retainer.
 17. The device asclaimed in claim 16, wherein means for conveying fluids through at leastone channel which is defined between the jacket surface of the supportand the inner surface of the recess are also provided.
 18. The device asclaimed in claim 17, wherein the means for conveying fluids comprise atleast one fluid reservoir and one pumping device.
 19. The device asclaimed in claim 17, wherein the means for conveying fluids are formedby the support, acting as a piston, and the retainer recess, serving asthe fluid reservoir.
 20. The device as claimed in claim 19, wherein thesupport comprises, at its front side, a threadless cylindrical sectionwhose outer diameter essentially corresponds to the inner diameter ofthe retainer recess.
 21. The device as claimed in claim 20, wherein apassage which communicates with the thread of the support, on the onehand, and, on the other hand, with the retainer recess when the supportis screwed in, is chased in the threadless cylindrical section.
 22. Thedevice as claimed in one of claims 16 to 21, wherein radial drill holeswhich communicate with a central drill hole which is provided in thesupport are chased in the jacket surface of the support.
 23. The deviceas claimed in one of claims 16 to 22, wherein means for applying thetargets or samples in the form of individual defined spots or fluiddroplets are also provided.
 24. The device as claimed in one of claims16 to 23, wherein at least one functionalizable track or drill hole ischased in the jacket surface.
 25. The device as claimed in claim 24,wherein the track runs essentially parallel to the jacket line of thesupport.
 26. The device as claimed in claim 24, wherein the track runshelically on the jacket surface of the support.
 27. The device asclaimed in claim 26, wherein the helical track on the jacket surface ofthe support forms a thread track and wherein the cylindrical recess inthe retainer exhibits a complementary counterthread which is designedsuch that, after the support has been screwed into the retainer, achannel, through which fluid can be conveyed, is formed along the threadtrack.
 28. The device as claimed in claim 27, wherein the thread trackpossesses an essentially rectangular or trapezoidal thread profile or isdesigned as a metric ISO thread, round thread or pipe thread.
 29. Thedevice as claimed in one of claims 16 to 28, wherein the retainerexhibits an excitation and detection device for investigating thechemical or biological targets and/or probes.
 30. The device as claimedin claim 29, wherein the excitation and detection device is integratedinto the retainer.
 31. The device as claimed in claim 29, wherein theexcitation and detection device is arranged at the entrance outside therecess of the retainer.
 32. The device as claimed in one of claims 29 to31, wherein the detection device exhibits means for measuringchemiluminescence signals, fluorescence signals, absorption signals orradioactivity.
 33. The use of the device as claimed in one of claims 16to 32 for analyzing DNA or RNA.